The U.S. Food and Drug Administration (FDA) will not process Acorda Therapeutics‘ marketing application for Inbrija (CVT-301), intended for the treatment of off-periods in Parkinson’s disease, until certain questions are answered.

The FDA’s refusal to accept Acorda’s new drug application (NDA) for Inbrija wasn’t based on safety or efficacy concerns, but was related to the drug candidate’s manufacturing process. In a preliminary review, the FDA found the application lacked certain information needed for a complete review.

Acorda will now seek guidance from the agency to resolve the issues as quickly as possible. They will also ask the FDA to clarify what additional information they require to process the application.

“We will work with the FDA as quickly as possible to address the open issues and to clarify the path to successfully refile our application,” Ron Cohen, MD, Acorda’s president and CEO, said in a press release.

Inbrija — an inhaled preparation of levodopa — is developed to treat the re-emergence of motor symptoms, often called “off-periods” in Parkinson’s disease patients who take oral levodopa or carbidopa.

Acorda presented data from the SPAN-PD Phase 3 trial (NCT02240030) of Inbrija in June, showing that the higher dose of the drug — 84 mg up to five times a day — showed improved movement after 12 weeks of treatment compared to patients who received a placebo inhalation.

The study, which included 339 Parkinson’s patients, supported findings from an earlier Phase 2b trial that showed better movement ability and less off-time in Inbrija-treated patients.

Another Phase 3 study (NCT02352363), however, failed to show that Inbrija improved lung function among treated patients — a feature Acorda had hoped for.

In its Refusal to File letter to Acorda, the FDA wrote that the application did not specify a date when the drug manufacturing site would be ready for inspection. They also had a question about the submission of the drug master production record.

While these two reasons were the basis of the refusal, the agency also requested additional information from Acorda when the NDA was resubmitted.

The FDA’s rejection of the NDA for Inbrija is the second setback for Acorda in a short time. In late March, a federal court invalidated four patents covering the drug Ampyra (dalfampridine), which improves walking in patients with the neurological disease multiple sclerosis.

The court ruling leaves the door open for other companies to produce generic versions of the drug.

Nevertheless, the company appears convinced that Inbrija will reach Parkinson’s patients in the near future.

“We remain confident in Inbrija’s data package and its promise as an important new therapy for people with Parkinson’s disease,” Cohen said. “We see tremendous long-term value in its solid clinical profile … and we remain focused on working to bring patients this important new therapy.”

Magdalena holds an MSc in Pharmaceutical Bioscience and an interdisciplinary PhD merging the fields of psychiatry, immunology and neuropharmacology. Her previous research focused on metabolic and immunologic changes in psychotic disorders. She is now focusing on science writing, allowing her to culture her passion for medical science and human health.